Solve Leetcode/Kattis problems

A C++/Java programmer who is into competitive programming. Need around 30 problems to be done from a competitive programming website called kattis. Problems are similar to leetcode questions but it’s not from leetcode here.Of 30 problems you do, atleast 20 of these should be of difficulty level >=5.5 . For every problem solved write a brief two page summary of your journey in developing the solution, like your approach to solve, lessons you learned, references to online resources, any notorious bugs that cost you long time, or some test cases you crafted that really rocked.